Railway signaling



1937. G. R. PFLASTERER RAILWAY SIGNALING Filed March 26, 1956 2 Sheets-Sheet l INVENTOR George 12, Zasterezz m5" ATTORNEY Dec. 21, 1937.

G. R. PFLASTERER RAILWAY S IGNALING 2 Sheets-Sheet 2 Filed March 26, 1936 INVENTOR HIS ATTORNEY Patented Dec. 21, 1937 h UNITED STATES ATENT OFFICE RAILWAY SIGNALING George R. Pflasterer, Swissvale, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa, a corporation of Pennsylvania Application March 26, 1936, Serial No. 70,925

12 Claims. (01. 246-50) My invention relates to railway signaling, and unit L is capable of assuming a horizontal or a particularly to signaling involving wayside Sigvertical position but not a 45 position. 7

vnals located along a track-way for governing the For controlling the signals, eachsection is propassage of trains. vided with a direct current neutral home relay tion is similar to the system shown in application designated by the reference characters H and D, Serial No. 26,784 of James J (Vanhorn, filed June respectively, each with a prefix the same as the 15, 1935, and the system shown in application reference character of the associated signal. Serial No. 66,002 of Henry S. Young, filed 'Febru- Also for controlling the signals, each section is 10 my 2-7, 1926. provided with an alternating current auxiliary 1 A feature of my invention is the provision of relay designated by the reference character J novel and improved apparatus for establishing a with a prefix the same as the reference character distinctive control for each of three track sections of the associated signal. 7 in the rear of an occupied section. Each dis- Each section is provided with three line wires tinctive control is effective to causea corresp'ondeach extending through the section and each 5 ing aspect of the associated wayside signal, including a front contact of each of the associ whereby there is produced a three-block, fourated track relays. The associated relay H is diindication, system of signaling. rectly connected with two of these line wires and I will describe one form of apparatus embody the associated relay Dis connected with the third ing my invention, and will then point out the wire and with onewire of the pair connected to novel features thereof in claims. the associated relay H. The associated relay J In the accompanying drawings, Figs. 1A and is connected to the same two wires as the relay 1B are diagrammatic views which, when placed D through a transformer and a condenser desend to end in the order named, illustrate one ignated by the reference characters M and F, N

form of three-block, four-indication, signaling respectively, each with a prefix the same tasthe system embodying my invention. reference character of the associated signal.

Similar reference characters refer to similar The'relatively high impedance of the relays H parts in each of the views. and D will prevent the flow of alternating cur- Referring to the drawings, the reference charrent in these relays and the transformers and The signaling system provided by this invenand with a direct current neutral distant relay 5 acters 8 and 9 designate the rails of a stretch of condensers will prevent the flow of direct cur railway track along which trafficflnormally moves rent in the alternating current relays J. in the direction indicated by the arrows. The Each section is provided with a suitable source rails 8 and 9 are divided by insulated joints M of direct current here shown as a battery l6 with into track sections W--X, X-Y, and Y-Z. As its terminals designated by the reference char- 5 here shown, each track section is divided into two acters B and C. subsections IT, 2T, 3T, 4T, etc. Each section is also provided with a trans- Each subsection is provided with a track batformer d si nat d by h f r n ch ract r N tery l5'connected across the rails at one end of with a p fi the s a t reference ara the subsection and with a track relay, designated ter of the associated signal and having a primary 40 by the reference character TR with a prefix the winding ll and a secondary winding 8. The sec- 40 same as the numerical prefix of the associated ondary winding I8 of each transformer N is con-' subsection, connected across the rails at the other nected in series, with the third line wire for the end of the subsection. section next in rear so that when alternating For governing the passage of trains along the current is supplied to the primary winding l1, stretch, each track section is provided with a alternating current will flow overthe line circuit 45 wayside signal designated by a suitable distinfor the control of the relay J for the section next guishing reference character. These signals may in rear. take any one of several forms of signal mecha- For supplying alternating current to the prinisms such as Searchlight, color light, position mary winding I! of the transformers N, each light, or semaphore. As here shown, each signal section is provided with a device, designated by 50 is of the semaphore type and includes an upper the reference character A with a prefix the same indication unit U and a lower indication unit L. as the reference character of the associated sig Each unit U is capable of assuming a horizontal nal, for converting direct current into alternator stop position, a 45 or caution position, ing current. As here shown, each device A is an and a vertical or proceed position, and each alternator of the well-known tuned reed type. 55

Referring to alternator IDA, for example, the reference character 2| designates a reed which is caused to vibrate between terminals 22 and 23 by a control winding 24. In the deenergized condition, reed 2| does not connect with either terminal 22 or terminal 23 but does connect with the terminal 25. When energy is supplied to the alternator IDA, winding 26 will attract reed 2| causing it to connect with terminal 23 and to move away from terminal 25, causing winding 24 to become deenergized. Upon the deenergization of winding 24, the resilience of reed 2| will cause it to move away from terminal 23 and to connect with terminal 22 as well as with terminal 25. The circuit for winding 24 will'then be completed so that reed 2| again'will go through the cycle of operation just described. Winding 24, therefore, will be repeatedly energized and deenergized as long as energy is supplied to its control circuit. When reed 2| connects with terminal 22 current is then supplied to the right-hand portion of primary winding of'transformer lllN; and when reed 2| connects with terminal 23, current is then supplied in the opposite direction to the left-hand portion of primary winding 1?. Alternating current, therefore, will be induced in the secondary winding I8 of transformer ION.

The alternator A for each of the other sections functions to supply alternating current to the associated transformer N in a manner identical to that described for alternator IQA.

Each battery I6 is directly connected to the line circuit for the control of the relay H for the section next in rear so that when that section is unoccupied, the associated relay H will be energized. Each 1 relay H controls the line circuit for governing the relay D for the section next in rear so that this rear line circuit will be energized whenever the relay H is energized. Each relay D controls the associated alternator A so that whenever the relay D is energized, the line circuit for the control of the relay J for the section next in rear is supplied with alternating current.

The relays H, D, and J, control the associated signal in the following manner; When the re-- lay H is deenergized (see signal l3), both semaphore arms U and L are in the horizontal position to indicate stop. When the relay H only is energized (see signal I2) a caution circuit for the upper semaphore arm U of that signal is closed over a path which passes from terminal B through front contact 25 of relay |2H and semaphore arm U to terminal C. Signal l2, therefore, is displaying its upper semaphore arm U in the 45 position and its lower semaphore arm L in the horizontal position to indicate approach next signal prepared to stop. When the relays H and D are both energized but the relay J is deenergized (see signal II), the caution circuit for the upper semaphore arm U of that signal remains closed over front contact 26 of relay IH and a proceed circuit for the lower semaphore arm L of that signal is closed over a path which passes from terminal B through front contact 26 of relay III-I, front contact 21 of relay ID, back point of contact 28 of relay IIJ, and lower semaphore arm L to terminal C. Signal I, therefore, is displaying its upper semaphore arm U in the 45 position and its lower semaphore arm L in the vertical position to indicate approach next signal at medium speed. When relays H, D, and J are all energized (see signal ID), the caution circuit for upper semaphore arm U remains closed over front contact 26 of relay NIH and a proceed circuit for the upper semaphore arm U is closed over a path which passes from terminal B through front contact 26 of relay lElH, front contact 21 of relay MD, and front point of contact 28 of relay NJ to upper semaphore arm U and terminal C. Signal l0, therefore, is displaying its upper semaphore arm U in the vertical position and its lower semaphore arm L in the horizontal position to indicate proceed at normal speed. 7

As here shown, a train K is indicated diagrammatically in the section immediately to the right of location Z so that all line circuits are open with the result that the relays |3H, |3D, and 3.1 are all deenergized.

Under this condition, relays |2D and |2J are deenergized but relays |2H, ||H, andIflH are all energized over easily traced circuits by battery I6 located at signals l3, I2, and II, respectively, since the sections associated with these relays are all unoccupied.

Since relay 2H is energized, relay ID is energized over a circuit which passes from terminal B of battery H5 at signal l2, through front contact 29 of relay I2H, secondary winding |8 of transformer I2N, front contact 3|) of relay 4TB, front contact 3| of relay 3TB, relay ||D, front contact 32 of relay 3TB, and front contact 33 of relay 4TB to terminal C of battery l6. Since relay IH is energized, relay IUD is also energized over an easily traced circuit similar to the circuit just traced for relay ||D.

When relay ND is energized, the operation of alternator HA is initiated by the closing of front contact 34 of relay D so that primary winding 35 of transformer IUM is supplied with alternating current over a path which passes from one terminal of secondary winding l8 of transformer UN through front contact 36 of relay 2TB, front contact 31 of relay lTR, primary the line circuits for the control of the'signal (not shown) for the section next in rear of location W are all energized so that that signal also will be displaying the normal proceed indication.

When the train K passes out of the section immediately to the right of location Z, relay |2D will become energized so that alternating current will be supplied to the line circuit for the control of relay NJ to cause signal I! to display the normal proceed indication.

From the foregoing description of the apparatus embodying my invention, it will be apparent that I have provided simple and reliable apparatus for establishing a threeeblock, four-indication, system of signaling wherein but three line control wires are required and wherein no polechanging apparatus is necessary.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a section of railway track,

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a home-and a distant relay for said section'con trolled over separate circuits including at least three conductors extending through the section, means controlled by traflic conditions for supplying current of one character to the circuit for said home relay when the sectionis'unoccupied and for also supplying current of said one character to the circuit for the distant relay under certain trafiic conditions in advance of said section, another circuit for said section including an "auxiliary relay, and at least two or" said conductors, means responsive to other trailic conditions in advance of said section for supplying-current of a ,differentcharacter to said other circuit for selectively controlling said auxiliary relay, and traflic governing means for said section controlled by said three relays.

2. In combination, a section of railway track, a .first line circuit for said section including a pairof line conductors, a'second line circuit .for said section including another line conductor'and oneconductor of said pair, a third line circuit also including the last mentionedpair of conductors, track circuit means forgoverning each of said circuits, means for :energizlhg said first circuit with current of one character, means governed by trafi'lc conditions inadvanceof said section for energizing said secondcircuit with ourrentof said one character; means governed by other; trafiic conditions in advance or said section for energizing said third circuit with current of a different character, a first and .asecond relay governed by said first and second line circuits respectively, another relay governed by said third circuit, and trafiic governing means for said section governed'bysaid three relays.

3. In combination, a section of railway track, a home and a distant relay as well as an auxiliary relay for said section, means for energizing said home relay provided said section is unoccupied, means governed by traific conditions in advance of said section for energizing said distant relay provided said section is unoccupied, means governed by other traffic conditions in advance of said section for energizing said auxiliary relay provided said section is unoccupied, a signal .for said section including a first indication unit and a second indication unit, a circuit for said first unit including a front contact of said home relay, another circuit for said first unit including a front contact of said distant relay and a front contact of said auxiliary relay, and a circuit for said second unit including a front contact of said distant relay and a back contact of said auxiliary relay.

4. In combination, a section of railway track, a first relay and a second relay, means governed by trailic conditions in advance of said section for energizing said first relay only or for energizing said second relay simultaneously with the energization of said first relay, a first line circuit for said section energized when said section is unoccupied, a second line circuit for said section energized when said first relay is energized, a third line circuit for said section energized when said second relay is energized, a home and a distant and an a xiliary relay governed by said three line circuits respectively, and a signal for said section governed by said last mentioned relays.

5. In combination, a section of railway track, a first relay and a second relay, means governed by trafiic conditions in advance of said section for energizing said first relay only or for energizing said second relay simultaneously with the energization of said first relay, a first line circuit for said section energized by direct current when said section is unoccupied, a second line circuit for said section energized by direct current when said first relay is energized, a third line circuit for saidsection energized by alternating current when said second relay is energized, two direct current relays governed by said first and second line circuits respectively, an alternating current relay governed by said third line circuit, and a signal for said section governed by said two direct current relays and by said alternating current relay.

.6. In combination, a section of railway track, a

first relay and a second relay, means governed by traffic conditions'in advance of said section for energizing only said first relay or for encrglzing said second relay simultaneously with the energization of said first relay, a first line circuit for said section including a pair of line wires, a second line circuit for said section including another line wire and one wire of said pair of wires,

' a transformer having a primary winding and a secondary winding, a third line circuit for said section including said secondary winding com nected in series with the last mentioned pair of line wires,.means for energizing said first line circuit with direct current when said section is unoccupied, means for energizing said second line circuit with direct'current when said first relay is energized, means for energizing said primary winding with alternatingcurrent when said second relay is energized, two direct current relays controlled by said first and second line circuits respectively, an alternating current relay con trolled by said third line circuit, and a signal for said section governed by said three last mentioned relays.

7. In combination, a section of railway track, a first relay and a second relay, means governed by trafiic conditions in advance of said section forenergizing onlysaid first relay or for energizing said second relay simultaneously with the energization of said first relay, a first line circuit for said section including a pair of line wires, a second line circuit for said section including another line wire and one wire of said pair of wires,

a transformer having a primary winding and asecondary winding, a third line circuit for said section including said secondary winding connected in series with the last mentioned pair of line wires, means for energizing said first line circuit with direct current when said section is unoccupied, means for energizing said second line circuit with direct current when said first relay is energized, means including an alternator for energizing said primary winding when said second relay is energized, two direct current. relays and an alternating current relay governed by said three line circuits respectively, and a signal for said section governed by said last mentioned relays.

8. In combination, a section of railway track, a first relay and a second relay, means governed by traffic conditions in advance of said section for energizing only said first relay or for energizing said second relay simultaneously with the energization of said first relay, a first line. circuit for said section including a pair of line wires, a second line circuit for said section including another line wire and one wire of said pair of Wires, a transformer having a primary winding and a secondary winding, a third line circuit for said section including said secondary winding connected in series with the last mentioned pair of line wires, means for energizing said first line circuit with direct current when said section is unoccupied, means for energizing said second line circuit with direct current when said first relay is energized, an alternator connected to said primary winding, means for energizing said alternator when said second relay is energized, two direct current relays and an alternating current relay controlled by said three line circuits respectively, and a signal for said section governed bysaid last mentioned relays.

9. A railway signal system comprising a stretch of railway track divided into sections, a track circuit including a track relay for each section,

a first and a second and a third line circuit for each section each governed by the associated track relay, means for each section for energizing the associated first line circuit, means for each section for energizing the associated second line circuit, provided the section next in advance is unoccupied, means for each section for energizing the associated third line circuit provided the two sections next in advance are both unoccupied, a first and a second and a third line relay for each section governed by the three associated line circuits respectively, and traflic governing means for each section governed by the associated line relays.

10. A railway signal system comprising a stretch of railway track divided into sections, three signal control relays for each section, means for each section effective when such section is unoccupied for energizing only one of the associated relays or for energizing only two of the associated relays or for energizing all three of the associated relays in accordance with trafiic conditions in advance of the associated section, and a signal for each section controlled by the associated three relays and arranged to display one proceed indication or another proceed indication or still a different proceed indication according as only one or only two or all three relays respectively are energized.

11. In combination, a plurality of successive block sections of railway track each having a first line circuit including a pair of line conductors and a second line circuit including another line conductor and one conductor of said pair, means governed by traffic conditions in each section for controlling the circuits through the line conductors for said section, each section having a first direct current relay supplied with current by said first line circuit and a second direct current relay supplied with current by said second line circuit, each section having associated there with means for supplying direct current to the first line circuit. of the adjacent section in the rear, each section having means controlled by the supply of directcurrent to the first line circuit for supplying direct current to the second line circuit of the adjacent section in the rear, each section having an alternating cmrent generator operated on the supply of direct current to supply alternating current to a circuit including two of the line conductors of the first and second line circuits of the adjacent section in the rear, the supply of direct current to said generator being controlled by one of the direct current relays for the section with which the generator is associated, each section having a third relay responsive only to alternating current supplied to the line conductors for such section, and a signal for each section controlled by said first, second and third relays.

12. In combination, a section of railway track, a first direct current relay and a second direct current relay controlled over separate line circuits including at least three conductors extending through the section, a third line circuit for said section including an alternating current relay and at least two of said conductors, track circuit means governing each of said line circuits, an alternating current generator operated on the supply of direct current to supply alternating current to the-third line circuit of the adjacent section in the rear, means controlled by trafiic conditions in advance of said section for supplying current of the appropriate character to one of said line circuits, means controlled by said relays for selectively supplying current of the appropriate character to the line circuits of the adjacent section to the rear, means controlled by one of said direct current relays for supplying direct current to said alternating current generator, and traffic governing means for said section controlled by said three relays.

GEORGE R. PFLASTERER. 

